using System;
using System.Collections.Generic;
using System.Linq;
using Newtonsoft.Json;
using RudderSdk.Core.Models;

namespace RudderSdk.Core;

public sealed partial class ScenarioService
{
    private void Persist()
    {
        var store = _client.Options.PlanStateStore;
        if (store == null)
            return;

        if (_runs.Count == 0)
        {
            store.State = null;
            return;
        }

        var state = new PersistedScenarioState
        {
            Runs = _runs.Values.Select(run => run.ToPersisted()).ToList()
        };
        store.State = JsonConvert.SerializeObject(state);
    }

    private sealed class RuntimeRun
    {
        public RuntimeRun(string runId, ExecutionPlan plan)
        {
            RunId = runId;
            Plan = plan;
        }

        public string RunId { get; }
        public ExecutionPlan Plan { get; }
        public Dictionary<string, ActiveNodeState> ActiveNodes { get; } = new();
        public HashSet<string> CompletedHandles { get; } = new(StringComparer.Ordinal);

        public PersistedRun ToPersisted()
        {
            return new PersistedRun
            {
                RunId = RunId,
                Plan = Plan,
                ActiveNodes = ActiveNodes.Values.ToList(),
                CompletedHandles = CompletedHandles.ToList()
            };
        }

        public static RuntimeRun FromPersisted(PersistedRun saved)
        {
            var run = new RuntimeRun(saved.RunId, saved.Plan);
            if (saved.ActiveNodes != null)
            {
                foreach (var node in saved.ActiveNodes)
                {
                    if (!string.IsNullOrEmpty(node?.NodeId))
                        run.ActiveNodes[node.NodeId] = node;
                }
            }
            if (saved.CompletedHandles != null)
            {
                foreach (var handle in saved.CompletedHandles)
                    run.CompletedHandles.Add(handle);
            }
            return run;
        }
    }

    private sealed class PersistedScenarioState
    {
        public List<PersistedRun>? Runs { get; set; }
    }

    private sealed class PersistedRun
    {
        public string RunId { get; set; } = string.Empty;
        public ExecutionPlan Plan { get; set; } = null!;
        public List<ActiveNodeState>? ActiveNodes { get; set; }
        public List<string>? CompletedHandles { get; set; }
    }

    private sealed class ActiveNodeState
    {
        public string NodeId { get; set; } = string.Empty;
        public DateTimeOffset? WaitDeadlineUtc { get; set; }
    }
}